Apparatus and method for filter cleaning by ultrasound, backwashing and filter movement during the filtration of biological samples

Abstract

The present application is directed to the separation of—a solid fraction from a fluid sample particularly a therapeutic cellular fraction from a biological sample such as a bone marrow sample by a porous filter ( 2 ) which separates a filtration unit ( 1 ) into an upper pre-filtration chamber ( 3 ) into which a fluid sample ( 4 ) requiring cell separation is introduced and a lower post-filtration chamber ( 5 ) into which a fluid ( 6 ) capable of transmitting an acoustic standing wave is introduced. An acoustic element ( 8 ) is coupled to a substrate ( 7 ) which is located within and at the bottom of the lower chamber ( 5 ) and which resonates in response to the acoustic generating element ( 8 ) and generates a standing wave through the two fluid phases and the filter to agitate the sample ( 4 ). Simultaneously, a cyclic process of vacuum draw ( 9 ). causes movement of the sample ( 4 ) downwards through the filter ( 2 ). Vacuum pressure, fluid flow rate and frequency of vibration are controlled from a remote unit housing appropriate pumps and valves.

1. An apparatus for separating a solid fraction from a fluid sample, the apparatus comprising a filtration unit, the filtration unit comprising;
 i. an acoustic wave generating element; 
 ii. at least one filter which divides the unit into a pre-filtration chamber for receiving the fluid sample and a post-filtration chamber for receiving a fluid capable of transmitting acoustic waves; and 
 iii. a substrate configured to be associated with the post-filtration chamber, the substrate being capable of resonation upon application of an acoustic wave thereto; 
 iv. wherein the acoustic wave generating element is configured to be associated with the substrate such that the acoustic wave generating element causes resonation of the substrate which in turn transmits an acoustic standing wave having a frequency in the range of between about 300 Hz and about 700 Hz through both the fluid within the post-filtration chamber and the fluid sample within the pre-filtration chamber. 
 
     
     
       2. The apparatus of  claim 1 , wherein the acoustic element is reversibly coupled to the substrate. 
     
     
       3. The apparatus of  claim 1 , wherein the apparatus is configured to sequentially move the fluids in the pre- and post-filtration chambers in opposing directions across the filter such that the net movement of the fluid sample is into the post-filtration chamber. 
     
     
       4. The apparatus of  claim 1 , wherein the at least one filter is agitated during the separation process. 
     
     
       5. The apparatus of  claim 3 , wherein the filter is associated with a holder capable of vibrating the filter in a vertical or a lateral direction or a combination thereof. 
     
     
       6. The apparatus of  claim 1 , wherein the fluid sample comprises a liquid. 
     
     
       7. The apparatus of  claim 6 , wherein the liquid comprises a biological sample. 
     
     
       8. The apparatus of  claim 7 , wherein the biological sample comprises a blood sample, an effusion, a urine sample, semen, bone marrow aspirate, spinal fluid, a cell suspension from tissue, mucus, sputum or saliva. 
     
     
       9. The apparatus of  claim 1 , wherein the solid fraction comprises a cell fraction. 
     
     
       10. The apparatus of  claim 9 , wherein the cell fraction comprises a white blood cell fraction. 
     
     
       11. The apparatus of  claim 9 , wherein the cell fraction comprises an undifferentiated cell selected from stem cells and progenitor cells. 
     
     
       12. The apparatus of  claim 1 , wherein the filter is manufactured of a synthetic material. 
     
     
       13. The apparatus of  claim 1 , wherein the filter comprises a plurality of pores and wherein the pore diameter is between about 2 and 4 microns. 
     
     
       14. The apparatus of  claim 13 , wherein the pore diameter is about 3 microns. 
     
     
       15. The apparatus of  claim 1 , wherein the apparatus is automated. 
     
     
       16. A method of separating a solid fraction from a fluid sample, the method comprising the steps of;
 a. introducing a fluid sample into the apparatus of  claim 1 ; 
 b. filtering the fluid sample; and 
 c. removing the separated fraction from the pre-filtration chamber. 
 
     
     
       17. The method of  claim 16 , further comprising the step of agitating the fluids in the pre- and post-filtration chambers by acoustic waves, wherein the agitation is continuous throughout the separation process. 
     
     
       18. The method of  claim 16 , further comprising the step of agitating the fluids in the pre- and post-filtration chambers by acoustic waves, wherein the agitation is pulsed throughout the separation process. 
     
     
       19. The method of  claim 16 , wherein the method further comprises the step of sequentially moving the fluids in the pre- and post-filtration chambers in opposing directions across the filter such that the net movement of the fluid sample is into the post-filtration chamber. 
     
     
       20. The method of  claim 16 , wherein the method further comprises the step of agitating the filter during the separation process. 
     
     
       21. The method of  claim 20 , wherein the filter is associated with a holder capable of vibrating the filter in a vertical direction or a lateral direction or a combination thereof. 
     
     
       22. The method of  claim 16 , wherein the fluid sample comprises a liquid. 
     
     
       23. The method of  claim 22 , wherein the liquid comprises a biological sample. 
     
     
       24. The method of  claim 23 , wherein the biological sample comprises a blood sample, an effusion, a urine sample, semen, bone marrow aspirate, spinal fluid, a cell suspension from tissue, mucus, sputum or saliva. 
     
     
       25. The method of  claim 16 , wherein the solid fraction comprises a cell fraction. 
     
     
       26. The method of  claim 25 , wherein the cell fraction comprises a white blood cell fraction. 
     
     
       27. The method of  claim 25 , wherein the cell fraction comprises an undifferentiated cell selected from stem cells and progenitor cells.